In the field of dental implantology, before surgical placement of implants in a patient's mouth, an assembly of a prosthetic device and implants is custom fit to the patient's mouth. Custom fitting involves taking an impression of the patient's mouth in a known fashion and reproducing a facsimile of the patient's mandible and/or maxilla in the form of a model. Models may be comprised of gypsum or other materials. The models are mounted on a base. The custom fitting of the prosthetic device proceeds with the use of an implant analog that is placed in the model in a position analogous to the desired ultimate position into which the implant itself will be surgically implanted in the patient's mandible or maxilla. The prosthetic device can be a crown, bridge or a more complete set of prosthetic teeth.
The custom fitting procedure must be able to accommodate the great variability of the shape of the mandible or maxilla from patient to patient. Some fittings may require the implant analogs to be placed in the model. In some cases, the implant analogs may be disposed at an angle that is not vertical to the base. Where multiple implants will be used to support a prosthetic device, the angles at which each implant is placed in the model can vary. During the fitting procedure it is possible for one implant analog to properly engage the prosthetic device while a separate implant analog fails to engage properly or may even break. In the event adjustments are needed, delay, inaccuracy and other problems may arise where the prosthetic device and implant analogs must be removed from the top of the model, that is, from the side of the model engaging the prosthetic device. If only a single implant analog needs to be adjusted, it is problematic to remove the entire bridge and other implants. Where the angle of implant analogs vary, it is also problematic to remove them. If an individual analog is damaged it may be difficult to remove it without the time and consequent expense of removing the entire assembly.
Implant analogs represent the implant present in the mouth of the patient. If abutments are already mounted on the implant, the implant analogs can also represent the abutments. Likewise, implant analogs can also represent parts of the abutment and of the implant in some implant systems.
Implant analogs used to make master casts for subsequent production of custom-made prosthodontic superstructure in exact agreement with the implants in the jawbones are themselves known. The implant analog is included in the master cast, with the future prosthodontic superstructure being attached to the head of the implant analog and, after the implant superstructure has been produced, transferred to the implant inserted in the mouth of the patient.